The present invention relates to a method for cutting slices from fish fillers with the skin still on, wherein the fillet is fed toward a freezing drum causing freezing and anchoring of the fillet at the skin side, whereby the longitudinal direction of the fillet preferably is orientated in the circumferential direction of the drum, and wherein a cutting tool, preferably in the form of a driven endless band knife, is positioned with the operative cutting edge thereof at a (radial) distance from the drum mantle surface, and wherein, from the fillet adhering to the drum through freezing, a fish meat slice is cut, the cutting plane extending substantially parallel with the drum circumference.
It is previously known methods and machines adapted to cut the skin from the fillet, wherein is utilized a rotating freezing drum, i.e. a drum being frozen down to beneath the freezing point. When wet fillets with the skin side thereof come into contact with the rotating freezing drum, they become frozen to the circumferential surface of the drum, where they are kept securely in place while being conducted toward a cutting device in the form of a band knife which cuts the fillet free from the skin, and wherein the skin is scraped off from the drum by means of a scraper means following the band knife and permanently contacting the drum surface. This known method and machine are well suited for skinning (flaying) fish fillets, but they are not suitable for cutting a toneless fillet slice at the skinless fillet side, and the stationary scraper means renders it impossible to divide a fillet into several parallel slices, each extending substantially parallel with the skin side.
Norwegian patent specification No. 54 801 discloses methods and devices for anchoring fish fillets upon the removal of the skin or other treatment. According to this patent specification, it is likewise used a retaining surface operating through freezing and which, thus, freezes the fillet during the skin removal or other treatment, whereafter the freezing of the fish fillet is neutralized through thawing. In rational fillet treatment, thawing is a too slow process.
Norwegian patent specification No. 109 486 discloses an apparatus for treating fish, comprising a conveyor movable along a closed path and having the form of a freezing surface retaining the fish through freezing during the treatment, the fish in frozen position being conveyed past a stationarily placed treating tool. The movable freezing conveyor consists of a freezing drum assigned a scraper means permanently attacking on the external mantle face of the drum, serving to scrape off those pieces of the fish which have become frozen to the drum as well as to scrape off any hoar and ice formations. This known apparatus is especially well suited for the skinning of herring; it does not allow to divide a fish fillet "into layers" parallel with the skin side.
With filleting, processing and further cutting of fine kinds of fish such as salmon and trout, it has been found that dividing the fillet into several slices substantially parallel with the two main faces of the fillet may result in substantial advantages in various connections. Such a division of salmon and trout will i.a. result in a quicker smoking of such slices, resulting in a better quality product, simultaneously as the wastage is reduced.
Thus, each fillet is cut into two or more such slices, parallel with the main faces of the fillet.